Certified Information Systems Auditor CISA · Free Practice Question Medium
Question 63
Sender of the message wants to ensure that the message should not change during the delivery process. To ensure this, he creates a hash of the message. He then encrypts the hash by using an encryption key.
On receipt of the message, the receiver will decrypt the message and compare the hash to ensure that message is not changed.
Which of the following keys is used by the sender of the message to encrypt the hash of the message?
- A A.sender's private key
- B B.sender's public key
- C C. receiver's private key
- D D.receiver's public key
Reveal correct answer
Correct answer: D
Explanation
Correct answer: D). receiver's public key Explanation: In this scenario, the objective is to ensure integrity of the message. Integrity refers to correctness, completeness, and accuracy of the data. Best way to ensure integrity is to encrypt the hash of the message using the receiver's public key. Following steps will help you to understand: Step 1: Sender will generate hash of the message Step 2: Sender will encrypt the hash using receiver’s public key. Step 3: Sender will send (i) message and (ii) encrypted hash to receiver. Step 4: Receiver will decrypt the encrypted hash using receiver’s private key. Step 5: Receiver will again generate hash of the message. Step 6: Receiver will compare hash arrived in step 4 with hash arrived at step 5. If both the hash matches, then message integrity is ensured i.e. message is not changed during transmission.Discussion
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